1. Field of the Invention
The present invention relates to a beverage package used to cool its contents. The invention can be applied especially to the cooling of beverages contained in a can or bottle type closed package.
It is an object of the present invention to enable the consumption of a beverage at ideal temperature at all times and in all places.
There are mainly two physical methods for cooling the contents of a package or container. Firstly, there is cooling by the expansion of a gas according to the classic laws of thermodynamics which link temperature to pressure and, secondly, cooling by evaporation and adsorption, the principle of which lies in evaporating a liquid under the effect of depression sustained by adsorption of the vapors of said liquid.
2. Description of the Prior Art
Thus, for example the first method has been implemented in the French patent application No. FR 97 04531 which proposes the cooling of a canned beverage by means of an expansion of compressed gas. A cartridge of gas to be expanded is placed in a metal heat sink that is itself placed inside the can.
This approach has several drawbacks. Firstly, the gas cartridge takes up about half the volume of the beverage to be cooled. This is dictated by the quantity of gas needed to cool the beverage. Furthermore, the cost of a cartridge of compressed gas is high. This leads to a very sharp increase in the price of the can.
Much research has also been devoted in the prior art to the other method of cooling by evaporation and adsorption. Many devices have been proposed, associating an evaporator device, containing a liquid to be evaporated, with a container containing an adsorbent.
Thus, for example, a method of this kind has been implemented in autonomous devices such as portable refrigerators. The U.S. Pat. No. 4,126,016, of which an illustration is given in FIG. 1, proposes a disposable two-part cooling system. An evaporating container 107, consisting of a chamber containing the liquid to be evaporated, is within an enclosure 100 and another chamber containing the adsorbent 108 is outside, the two elements 107 and 108 being connected by a bayonet-type connection device 109.
This connection device 109 is however complicated to make, especially when a good vacuum is needed (the difficulty being related to the existence of moving parts in rotation and translation with a rubber seal). A device of this kind is not economical.
The application of the method of cooling by evaporation and adsorption has also been proposed for beverage packages.
Thus, the U.S. Pat. No. 4,736,599, of which an illustration is given in FIG. 2, proposes to make a heat exchanger 16 (evaporator device) totally contained within the container 10 to be cooled (explicitly described as a can). At the same time, this patent stresses the reversibility or two-way character of the intercommunication between the heat exchanger 16 and the adsorbent contained in a container 22 located beneath the can 10. This device has at least four valves: two to create the vacuum 19 and then fill 20 the exchanger 16, one to create the vacuum in the container 22 of the adsorbent and one to activate the cooling 27. A structure gives rigidity to the vacuum-tight chambers 16 and 22, and a tube 26 connects the different elements together. This complex construction certainly does not make for a cost price compatible with a disposable package such as a can, and the reversibility of the intercommunication contributes to this complexity.
Other patents, the U.S. Pat. No. 4,759,191, supplemented by the U.S. Pat. No. 5,048,301 by the same inventors, illustrated in FIG. 3, propose the cooling of a beverage 15 contained in a package 10 by means of a module 11 placed in the package 10 (presented as a can).
This module 11 consists of several chambers. A first chamber 12 contains the liquid (18) to be evaporated (water) and a second chamber 14, internal to the first chamber 12, contains desiccant 25 and "heat sink" 24. Activation means, which bring the water 18 and the desiccants 25 into communication, act as a pump for the water vapor. This reaction of adsorption which cools the first chamber 12 nevertheless causes a substantial release of heat in the second chamber 14. This heat may be trapped by particular materials 24 (by phase change or endothermal reaction). The second U.S. Pat. No. 5,048,301, in this respect, proposes to add a heat insulation feature (of the DEWAR type) by means of a vacuum chamber 13 surrounding the chamber 14 that contains the adsorbent 25.
None of the prior art inventions has seen any significant commercial application to date. This is because of technical reasons of performance and economic reasons of manufacturing cost. The present invention proposes solutions to these problems.
Indeed, certain technical and physical imperatives have never been seriously taken into account in the prior art, and the constraints of manufacturing costs are high, given the fact that the application concerns disposable devices.
The complexity of the devices proposed in the prior art is an evident obstacle to their development. The two-way intercommunication valves of the U.S. Pat. No. 4,736, 599, although not described in detail, are complex and expensive to manufacture. The U.S. Pat. No. 4,759,191 and the U.S. Pat. No. 5,048,301 suffer from the same economic constraints and also underscore the difficulty of removing the heat released in the package by the adsorbent, and the complex means that have to be used for this purpose.
Moreover, these devices cannot be used for to cool beverages rapidly. Indeed, two points essential to this kind of rapid cooling have not been sufficiently taken into account. The first point is the effectiveness of the heat exchange between the evaporator and the beverage, and the second point is the speed with which the vapors of the refrigerant liquid are pumped into the evaporator.
The pumping speed depends of course on the effectiveness on the adsorbent, and also on the geometrical characteristics of the means for making the evaporator communicate with the container of the adsorbent, and on the residual pressure of the non-adsorbable gases, namely gases other than the vapor of the refrigerant liquid.
Now, none of the prior art devices proposes any special arrangements to give an efficient vapor pumping rate. The different configurations proposed and the types of connection valves used suggest difficulties related to the geometry. But even more than these geometrical characteristics, it is the residual pressure of the non-adsorbable, and hence non-pumped, gases that limits the process.
The goal of the present invention is to overcome the drawbacks of the prior art.
The present invention proposes a self-cooling package for beverages whose working is based on the principle of the evaporation of a refrigerant liquid at reduced pressure.
To this end, the invention proposes a self-cooling package for beverages formed by two distinct elements.
The beverage package according to the invention contains cooling means consisting of an internal evaporator (a cavity) and means to connect these cooling means to pumping means external to the package. These pumping means cause and sustain the evaporation of a refrigerant liquid in the internal evaporator.
The internal cooling means and the external pumping means form the two distinct elements of the device according to the invention. They are connected by connection means but are independent in their design and manufacture.